1. Field of the Invention
The present invention relates to a hard disk drive, and more particularly, to a magnetic head parking system of a hard disk drive which enables stable parking of a magnetic head when an operation of the hard disk drive is stopped.
2. Description of the Related Art
A hard disk drive (HDD) is an auxiliary memory device of a computer which reproduces data stored on a magnetic disk or records data on the magnetic disk by using a magnetic head.
FIG. 1 is a plan view illustrating a conventional hard disk drive. FIG. 2 is a partial perspective view illustrating part of a conventional magnetic head parking system. FIG. 3 is a perspective view illustrating a portion A shown in FIG. 2.
Referring to FIGS. 1 and 2, a hard disk drive includes a magnetic disk (i.e., hard disk) 20 which is a recording medium to record data, a spindle motor 30 installed on a base plate 10 and rotating the magnetic disk 20, an actuator 40 having a magnetic head 41 to record the data on the magnetic disk 20 and to reproduce the data stored on the magnetic disk 20.
Typically, one or a plurality of the magnetic disks 20 are installed in the hard disk drive and separated a predetermined distance from each other and are rotatable by the spindle motor 30. A parking zone 21, where a slider 42, on which the magnetic head 41 is mounted, is placed when power is turned off, is provided at an inner circumferential side of the magnetic disk 20. A data zone 22, where a magnetic signal is recorded, is provided outside the parking zone 21.
The actuator 40 is rotatable by a voice coil motor 48 around a pivot shaft 47 installed on the base plate 10. The actuator 40 includes an arm 46 pivotably coupled to the pivot shaft 47, the slider 42 where the magnetic head 41 is mounted, and a suspension 44 installed at the arm 46 to support the slider 42 to elastically bias the slider toward a surface of the magnetic disk 20.
In the conventional hard disk drive having the above structure, during data recording/reproduction operations, a lifting force by a rotation of the magnetic disk 20 and an elastic force by the suspension 44 are applied to the slider 42 on which the magnetic head 41 is mounted. Accordingly, the slider 42 is maintained in a lifted state above the data zone 22 of the magnetic disk 20 at a height where the lifting force and the elastic force are balanced. Thus, the magnetic head 41 mounted on the slider 42 maintains a predetermined distance from the magnetic disk 20 while performing data recording and reproduction with respect to the magnetic disk 20. Further, when the power is turned off and the rotation of the magnetic disk 20 stops, the lifting force lifting the slider 42 stops. Thus, before the lifting force stops, the slider 42 should be moved from the data zone 22 of the magnetic disk 20 so that possible damage to the data zone 22 due to a contact between the slider 42 and the data zone 22 is preventable. Thus, when the arm 46 of the actuator 40 rotates to move the slider 42 to the parking zone 21 of the magnetic disk 20 before the magnetic disk 20 completely stops rotating, the slider 42 being placed in the parking zone 21, the damage to the data zone 22 is preventable.
When the power is turned on and the magnetic disk 20 resumes rotating, the lifting force is generated again and accordingly the slider 42 is lifted. The slider 42 in the lifted state is moved to the data zone 22 of the magnetic disk 20 by pivoting of the arm 46. The magnetic head 41 mounted on the slider 42 performs recording and reproduction of the data with respect to the data zone 22 of the magnetic disk 20.
Recently, as shown in FIG. 3, to facilitate lifting of the slider 42 by reducing a contact area between the slider 42 and the parking zone 21 of the magnetic disk 20, bumpers 21 a of crater-like shapes may be formed by a laser on the parking zone 21.
The above magnetic head parking system is referred to as a contact start stop (CSS) type magnetic head parking system.
A locking apparatus 50 may be provided to prevent a movement of the actuator 40 after the slider 42 is placed in the parking zone 21 of the magnetic disk 20. The locking apparatus 50 prevents the actuator 40 from unnecessarily pivoting by an external impact when the power is turned off. Thus, the data zone 22 can be prevented from being damaged due to the external impact by the magnetic head 41 directly contacting the data zone 22 since the slider 42 is prevented from moving from the parking zone 21 to the data zone 22 by the locking apparatus 50.
However, in the above CSS type magnetic head parking system, the suspension 44 and the slider 42 may be severely vibrated in upward and downward directions by the external impact when the power is turned off. In this case, the magnetic head 41 collides against a surface of the parking zone 21 of the magnetic disk 20 and is damaged. The locking apparatus 50 can only prevent the actuator 40 from pivoting due to an external impact, but does not prevent the movement in the upward and downward directions of the slider 42. Damage to the magnetic head 41 is frequently generated in the magnetic head parking system having the above structure.
Problems of the conventional magnetic head parking system will be described below with reference to FIG. 4. Referring to the FIG. 4, the parking zone 21 and the data zone 22 are provided at a lower surface of the magnetic disk 20. The suspension 44 and the slider 42 of the actuator 40 are disposed between the base plate 10 and the magnetic disk 20. The spindle motor 30 is installed on the base plate 10 by a flange 32. A hub 36 is rotatably installed at an outer circumference of a shaft 34 of the spindle motor 30 by providing a bearing 38 to interpose between the shaft 34 and the hub 36. The magnetic disk 20 is inserted around an outer circumference of the hub 36. A disk clamp 60 to fix the magnetic disk 20 to the hub 36 of the spindle motor 30 is coupled to an upper end portion of the spindle motor 30 by a screw 62.
In the above structure, when an external impact is applied to the hard disk drive in the state in which the magnetic head 41 is parked in the parking zone 21 of the disk 20, the suspension 44 and the slider 42 moves severely in the upward and downward directions so that a head slap phenomenon, in which the magnetic head 41 mounted on the slider 42 collides against the surface of the magnetic disk 20, is generated. Thus, when the external impact is applied to the hard disk drive in the state in which the operation of the hard disk drive stops, the suspension 44 which is flexible and elastic and the slider 42 installed at an end portion of the suspension 44 are severely moved in the upward and downward directions. Since the slider 42 is disposed between the magnetic disk 20 and the flange 32 of the spindle motor 30, a range of movement of the slider 42 is limited to a space between the magnetic disk 20 and the flange 32. As the movement range increases, the slider 42 is bounced so that an amount of an impact applied to the magnetic head 41 to collide against the surface of the magnetic disk 20 increases accordingly. In the conventional hard disk drive, an interval between the magnetic disk 20 and the flange 32 is rather large to facilitate a smooth pivot of the actuator 40 and to prevent interference thereof so that the movement range, in which the slider 42 is movable in the upward and downward directions, is considerably large. As a result, when a head slap is generated, the magnetic head 41 is easily damageable and the data recording/reproducing performance of the magnetic head 41 is lowered.